#include <iostream>

using namespace std;

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        if( root == p || root == q || root == nullptr) {
            return root;
        }

        TreeNode * left = lowestCommonAncestor(root->left, p, q);
        TreeNode * right = lowestCommonAncestor(root->right, p, q);

        if(left != nullptr && right != nullptr) {
            return root;
        } else if(left == nullptr) {
            return right;
        } else {
            return left;
        }
    }
};

int main()
{
    return 0;
}